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Abstract #60680 Published in IGR 16-4
Calcium channel blockade reduces mechanical strain-induced extracellular matrix gene response in lamina cribrosa cells
Quill B; Irnaten M; Docherty NG; McElnea EM; Wallace DM; Clark AF; O'brien CJBritish Journal of Ophthalmology 2015; 99: 1009-1014
PURPOSE: This study examines the effect of the L-type calcium channel blocker verapamil on mechanical strain-induced extracellular matrix genes in optic nerve head lamina cribrosa (LC) cells. METHODS: Changes in LC cell intracellular calcium [Ca(2+)]i following hypotonic cell membrane stretch were measured with the fluorescent probe fura-2/AM. Fluorescence intensity was measured, after labelling, by calcium (Ca(2+)) imaging confocal microscopy. Confluent human LC cell cultures were serum starved for 24 h prior to exposure to cyclical mechanical strain (1 Hz, 15%) for 24 h in the presence or absence of verapamil (10 mm). Transforming growth factor-β 1 (TGF-β1), collagen 6A3 (COL6A3) and chondroitin sulfate proteoglycan 2 (CSPG2) mRNA expression levels were assessed by quantitative RT-PCR. RESULTS: Hypotonic cell membrane stretch of LC cells from normal donors significantly increased [Ca(2+)]i (p<0.05). Exposure to cyclical mechanical strain (15% strain) produced a statistically significant increase in the three matrix genes that were examined (TGF-β1, COL6A3 and CSPG2). This response in both cyclical and mechanical stretch was significantly reduced by pretreating LC cells with the L-type calcium channel blocker verapamil (p<0.05). CONCLUSIONS: This study provides evidence of a novel mechanotransduction pathway linking mechanical strain, cation channel function and the induction of LC cell matrix gene transcription. This highlights the potential involvement of calcium influx in the activation of matrix remodelling responses in the optic nerve head and supports the rationale that calcium channel blockers may attenuate disease progression in glaucoma.
Institute of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland University College Dublin School of Medicine and Health Sciences, University College Dublin, Dublin, Ireland.
Full articleClassification:
3.8 Pharmacology (Part of: 3 Laboratory methods)
3.4.2 Gene studies (Part of: 3 Laboratory methods > 3.4 Molecular genetics)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
2.3 Sclera (Part of: 2 Anatomical structures in glaucoma)
